Runnin 188.8.131.529 and Chrome 18 (beta). It seems that some update made it so that when clicking the 1Password icon, the unlock password field is not focused when the window is shown, requiring you to click the field yourself. Minor annoyance but worth fixing.
Also if you try to use the browser extension to copy and paste username and password (for example when a site has moved the login process to somewhere where 1P won't find it properly despite having an entry for the site), you can copy username or password, then you have to search for the field again to get the other field. 1Password should maintain the extension's state for a while if you open an entry's data in it.